One way smoke and fire spreads from one part of a building to another is through passages or openings, often referred to as through-penetrations, in floors, walls, ceilings, or the like. Such openings are provided in the building to allow cables, wires, pipes or the like to pass from one area of the building to another.
One technique currently used to prevent the spread of fire and passage of smoke through such openings uses intumescent sheets that are cut to follow the contour of the penetrating cables. A bead of moldable intumescent putty is then provided along the perimeter of the sheets. Other techniques utilize intumescent bricks or pillows.
While such techniques are generally satisfactory for resisting the spread of fire and preventing the passage of smoke from one room or compartment of a structure to another, installation is time consuming and expensive. In addition, when intumescent sheets, bricks, or pillows are used, they must be mechanically attached to, or physically compressed in, the opening, or both, to pass the hose stream portion of the fire test defined in ASTM E814-02. In addition, firestops fabricated in this manner do not lend themselves to repeated re-entry without the likelihood of material damage or damage to the perimeter of the opening, do not remain in the opening during the cable work leading to potential omission of essential fire stop material upon re-closure, and do not lend themselves to ease of inspection without removal of at least a portion of the completed assembly. In addition, removing cables from a typical through-penetration currently requires the existing intumescent material to be removed, discarded, and replaced completely or in part with new intumescent material. This procedure is time consuming, expensive, and wasteful. Because through-penetrations may be opened and closed numerous times during the service life of an opening to add or remove items from the opening, the costs associated with such systems can be significant.
Furthermore, such systems, installed in floor openings, require cover plates to meet fire and architectural demands. Cover plates are typically made of 0.25 inch (6.4 millimeters) steel which makes them difficult to modify after initial fabrication and installation. Typically, such cover plates must be removed from the area of the through-penetration or even from the building to make necessary modifications. In addition, adjusting the contour of the cover to match the profile of the new cable bundle can be time consuming.
Techniques for fire stopping through-penetrations are also known in the prior art. U.S. Pat. No. 4,496,790 (Spencer), for example, discloses a self-anchoring poke-thru wiring device for the extension of communication and/or electrical wiring through a passage in a floor designed to prevent the spread of fire from one side of the floor to the other.
U.S. Pat. No. 4,493,173 (Kohaut) discloses a cable passage closure and sealing device for positioning in an opening in a structure such as a floor or wall that is used for passing or connecting a cable or cables and cable conduits there through. The device automatically expands and seals itself and the cables and the cable conduits in the structural opening upon exposure to excess heat or fire.
U.S. Pat. No. 4,304,079 (Thorsten) discloses a cable penetration matrix structure comprising a plurality of individual penetration cells that is cast into the building floor during construction.
These prior devices and techniques, however, tend to suffer from one or more disadvantages, drawbacks or shortcomings. For examples, these prior devices are mounted in the opening making installation difficult and occupying space in the opening that could otherwise be used to pass items from one room of the building to another. Accordingly, there exists a need in the industry for a method and apparatus for firestopping a through-penetration that is easy to install, allows the maximum percentage of the opening to be used to pass items through the partition, and allows items passing through the opening to be readily added or removed. Such a firestop device can provide considerable long-term cost saving to firestop users over currently available systems and techniques.